Moving iron ratiometer



1969 v. I. EFIMENKO 3,477,025

MOVING IRON RATIOMETER Filed April 12. 1967 United States Patent 3,477,025 MOVING IRON RATIOMETER Viktor Ivanovich Efimenko, Ulitsa Vystavochnaya 3, kv. 17, Krasnodar, U.S.S.R. Filed Apr. 12, 1967, Ser. No. 630,441 Int. Cl. G01r 7/00, 1/20; H01f /00 U.S. Cl. 324-140 3 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to electrical measuring instruments, and more particularly to moving-iron ratiorneters.

Known at present are moving-iron ratiometers comprising a fixed magnetized piece of iron with measuring coils and two split pole tips, and a cylindrically shaped movable piece of iron with a segment, partially entering the slots of the pole tips (cf. U.S.S.R. Authors Certificate, No. 157,734, class 21c, 3

The formation of the movable iron in the shape of a cylinder with a segment diminishes the cross section of the cylinder-to-segment connection area which results in a reduction of the maximum magnetic flux which can pass through the movable iron without saturating the latter.

Apart from this, it is not contemplated in said ratiorneter that a considerable surface area of the movable iron be used as the square surface of the air gaps between the pole tips and said movable iron.

The primary object of the present invention is to provide a moving-iron ratiometer with a higher permeance of the gaps between the pole tips and the movable iron by virtue of the maximum use of the surface of said core.

With this and other objects in view the present invention is aimed at providing a moving iron ratiometer, comprising a fixed magnetized iron with two measuring coils provided thereon and two split pole tips, and a movable piece of iron partially entering the slots of said pole tips. The movable iron is constituted as a plate and is fitted into the slots of an auxiliary pole tip, located between said pole tips.

Other objects and advantages of the present invention will become apparent from an exemplary embodiment described hereinbelow with due reference to the accompanying drawing, wherein:

FIG. 1 is a plan view which is cut away showing the moving-iron ratiometer of the invention;

FIG. 2 is a view in the direction of arrow A in FIG. 1;

FIGS. 3, 4 and 5 are elevation views of different embodiments of the movable iron; and

FIG. 6 shows an embodiment of the pole tip.

The moving-iron ratiometer comprises a magnetized piece of iron 1 with measuring coils 2 and 3 provided thereon and split pole tips 4, 5 and 6, and a movable iron 7 in the form of a plate and accommodated in the slots of pole tips 4, 5 and 6.

. Three magnetic fluxes are closed by movable iron 7 said fluxes are shown in FIG. 1 by broken lines):

3,477,025 Patented Nov. 4, 1969 I flux resulting from self-inductance of measuring coil 2;

I flux resulting from self-inductance of measuring coil 3, and

I flux resulting from mutual inductance of coils 2 and 3.

Said three magnetic fluxes create three driving torques M M and M which, depending upon the current values through coils 2 and 3, act upon movable iron 7 with the result that said iron assumes a certain position with respect to pole tips 4, 5 and 6. The torque M tends to shift movable iron 7 towards pole tip 4, the torque M towards pole tip 6, whereas the torque M tends to set movable iron symmetrically with respect to pole tips 4 and 6 The design and relative disposition of the suspended movable iron and the pole tips are such, that in any position of the movable iron up to 98 percent of its surface is used as the square surface of the air gaps between the pole tips and said iron.

To obtain a desired scale type of the ratiometer, the movable iron and the pole tips can be of various shapes, such as an arc of a circumference, straight line or templet curve.

The ratiometer is adjusted by turning pole tips 4 and 6 with respect to points 8 and 9 at which they are attached to magnetized piece 1.

To remove the spindle of the moving element (not shown in the drawings), said spindle accommodating the movable iron rigidly fitted thereto, pole tip 5 is provided either with an opening 10 (FIG. 1) or with a slot 11 (FIG. 6).

The herein described ratiometer will find preferable application in designing frequency meters.

Though this invention has been described herein with reference to a preferred embodiment, it will be understood that minor changes in the details of construction may be made without departure from the spirit and scope of the invention, as will be readily understood by those competent in the art.

What is claimed is:

1. A moving-iron ratiometer, comprising: a fixed magnetized piece of iron, two measuring coils on said magnetized piece of iron for producing three magnetic fluxes therein; three pairs of spaced, split pole tips coupled to said magnetized piece of iron and defining slots therebetween; and a movable iron member constituted as a plate and located in said slots of said pole tips for turning about an axis under the action of torques resulting from said magnetic fluxes.

2. A ratiometer as claimed in claim 1 wherein said three pairs of split pole tips comprise a first pair of spaced members, a second pair of spaced members in the same planes as said first members, and a third pair of spaced members between the first two pairs of members and with a smaller spacing therebetween, said plate extending into the spaces between said three pairs of spaced members.

3. A ratiometer as claimed in claim 2 wherein said first and second pairs of plates are pivotably connected to said fixed piece of iron.

References Cited UNITED STATES PATENTS 2,002,445 5/1935 Arey et al. 324- RUDOLPH V. ROLINEC, Primary Examiner A. E. SMITH, Assistant Examiner US. Cl. X.R. 324-147; 335--266 

